In certain digital applications, digital samples of an analog signal which are transferred from a digital system operating under a first sampling clock rate to a digital system operating under a second clock rate requires a so-called interpolator arrangement to interpolate between the sample clock rates. One way of providing such interpolation is disclosed in U.S. Pat. No. 4,527,020 issued July 2, 1985, to Y. Ito. In the Ito arrangement, a digital filter, commonly referred to as a transversal filter, is used to perform the interpolation in which the sampling interval of a first sampling clock signal (CK2) is divided into a plurality of segments each associated with a respective group of filter tap coefficients. Each digital sample to be interpolated at each occurrence of a second sampling clock signal (CK1) is obtained by supplying to the digital filter the group of tap coefficients associated with that segment of the interval which is present at the time of the second sampling clock signal.
The precision of the ITO interpolation arrangement may be improved by dividing the interval of the first sampling clock into a large number of segments. However, doing so requires the arrangement to store in memory a like number of different groups of tap coefficients. The storage of a large number of different tap coefficients becomes unwieldy, especially if the digital filter is a multi-tap transversal filter.